1. Field of the Invention
The present invention relates to charging systems, and more particularly, to a portable battery charger.
2. Description of the Related Art
Many battery chargers have been developed in the past. Applicant believes that one of the closest references corresponds to his own U.S. Pat. No. 5,998,961 issued on Dec. 7, 1999 for a portable battery charger. However, it differs from the present invention because in that invention, Brown teaches a portable battery charger for jump-starting an engine of a disabled vehicle including a main housing having a motor and a generator disposed therein. The main housing includes gasoline and oil intake portions in communication with the motor. A pair of cables extends outwardly from one of the sidewalls of the main housing. The pair of cables is in communication with the generator. The pair of cables each has a spring-loaded clip disposed on free ends thereof for operative coupling with positive and negative terminals of a battery.
Applicant believes that another reference corresponds to U.S. Pat. No. 5,212,952 issued to Yokoyama, et al. on May 25, 1993 for a compact power supply and lubricant-affording device therefore. However, it differs from the present invention because Yokoyama, et al. teach a compact portable electrical generator powered by a gas fueled internal combustion engine. A combined starter and generator are coupled to the engine for starting of the engine and for generating electrical power when the engine is running. The engine includes a lubricating system including lubricant that is supplied from a separately insertable lubricant cartridge and which is pumped by a hose compressing type of pump so as to insure adequate delivery of small amounts of lubricant regardless of the orientation of the unit and also so as to insure that lubricant cannot leak from the system when the unit is not being operated.
Applicant believes that another reference corresponds to U.S. Pat. No. 5,162,662, issued to Nakayama on Nov. 10, 1992 for a compact power supply with gas engine. However, it differs from the present invention because Nakayama teaches a compact portable power supply including an internal combustion engine that drives a generator and which engine is fueled by a pressurized source of gaseous fuel. The outer housing and control structure is configured in such a way that the source of gaseous fuel will always be oriented so that liquid fuel will not be delivered to the engine when the power supply is in use.
Applicant believes that another reference corresponds to U.S. Pat. No. 4,595,841, issued to Yaguchi on Jun. 17, 1986 for a full-covered portable generator. However, it differs from the present invention because Yaguchi teaches a full-covered portable generator composed of a generator core, an engine for driving the generator core enclosed by a cover comprising discrete front, rear and bottom cover elements. The rear cover element is detachably joined to the rear cover element along lateral peripheral surfaces of the generator. The engine and its main components are each covered at least in part by the front cover element in a manner that they are exposed when the rear cover element is detached from the front cover element, for facilitation of the maintenance thereof. Various controls and readouts or displays are arranged on the front cover element transversely of the generator, preferably in an order corresponding to the required order in which they are operated or read. A carrying handle is arranged on an upper surface of the front cover element and extends transversely of the generator.
Applicant believes that another reference corresponds to U.S. Pat. No. D309,892, issued to Troup on Aug. 14, 1990 for a portable generator for charging automobile batteries.
Applicant believes that another reference corresponds to U.S. Pat. No. 4,902,955, issued to Manis, et al. on Feb. 20, 1990 for a portable battery charger. However, it differs from the present invention because Manis, et al. teach an improved portable battery charger (10) for boosting and charging automotive-type batteries. The battery charger (10) comprises rectifier means (34), an automotive-type battery (20), and an air compressor (24) powered by the battery (20) received within a charger housing (12). Positive and negative charging cables (30) and (28), respectively are retractably received within first and second cable housings (14) and (16), respectively. The first and second cable housings are positioned adjacent oppositely disposed external walls of the charger housing (12) and are dimensioned such that the positive and negative charging clamps (76) and (70), respectively may be slidably positioned over saddle notches (72) defined by the cable housings when the charging cables are fully retracted into the cable housings whereby the charging clamps (76) and (70) are physically isolated from each other by the charger housing (12), thereby preventing accidental contact between the clamps. When connected to a source of AC power, the rectifier means (34) provides a DC charging voltage to the battery (20). The charging cables are connected to the terminals of the battery (20) to permit the boosting or jump-starting of a vehicle with a dead battery when AC power is not conveniently available.
Applicant believes that another reference corresponds to U.S. Pat. No. 5,444,592, issued to Shimizu, et al. on Aug. 22, 1995 for a portable power unit. However, it differs from the present invention because Shimizu, et al. teach a portable power unit that has a protective circuit for cutting off an output current from the power unit when the power unit is in an overload state. An amount of the output current is detected. An output voltage from the power unit is reduced when the amount of the output current detected reaches a first threshold value, thereby preventing the protective circuit from undesirably operating for one power unit when it is connected for another for parallel operation. When the amount of the output current decreases to a second threshold value, which is smaller than the first threshold value, with the power unit being in a state in which the output voltage is reduced, the voltage-reducing operation is canceled.
Other patents describing the closest subject matter provide for a number of more or less complicated features that fail to solve the problem in an efficient and economical way. None of these patents suggest the novel features of the present invention.